U.S. patent application number 15/322757 was filed with the patent office on 2017-05-18 for improved robotic working tool.
The applicant listed for this patent is HUSQVARNA AB. Invention is credited to Patrik Jagenstedt, Mattias Kamfors.
Application Number | 20170139419 15/322757 |
Document ID | / |
Family ID | 51059450 |
Filed Date | 2017-05-18 |
United States Patent
Application |
20170139419 |
Kind Code |
A1 |
Jagenstedt; Patrik ; et
al. |
May 18, 2017 |
IMPROVED ROBOTIC WORKING TOOL
Abstract
A robotic work tool system (200) comprising a charging station
(210) and a robotic work tool (100), said robotic work tool (100)
comprising a position determining device (190) and a controller
(210), wherein said controller (210) is configured to determine a
current position for the robotic work tool (100) based on the
position determining device (190), determine a first distance from
the current position to said charging station (210), cause said
robotic work tool (100) to travel a predetermined distance or for a
predetermined time, determine a new current position for the
robotic work tool (100) based on the position determining device
(190), determine a second distance from the new current position to
said charging station (210), determine if the second distance is
larger than the first distance; and if so, cause the robotic work
tool (100) to turn towards the charging station (210).
Inventors: |
Jagenstedt; Patrik;
(Tenhult, SE) ; Kamfors; Mattias; (Jonkoping,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HUSQVARNA AB |
HUSKVARNA |
|
SE |
|
|
Family ID: |
51059450 |
Appl. No.: |
15/322757 |
Filed: |
June 30, 2014 |
PCT Filed: |
June 30, 2014 |
PCT NO: |
PCT/EP2014/063803 |
371 Date: |
December 29, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G05D 1/0274 20130101;
B60L 2240/622 20130101; G05D 1/0265 20130101; B60L 50/52 20190201;
Y02T 10/7072 20130101; B60L 15/20 20130101; G05D 2201/0208
20130101; B60L 8/003 20130101; Y02T 10/72 20130101; A01D 34/008
20130101; Y02T 10/70 20130101; B60L 53/16 20190201; B60L 2240/421
20130101; G05D 1/028 20130101; B60L 50/66 20190201; B60L 2240/36
20130101; B60L 2260/32 20130101; G05D 1/0276 20130101; Y02T 90/12
20130101; Y02T 90/14 20130101; B60L 3/0061 20130101; G05D 1/0278
20130101; Y02T 10/64 20130101; B60L 53/36 20190201; B60L 1/003
20130101; G05D 1/0225 20130101; B60L 2200/40 20130101 |
International
Class: |
G05D 1/02 20060101
G05D001/02; B60L 11/18 20060101 B60L011/18; A01D 34/00 20060101
A01D034/00 |
Claims
1. A robotic work tool system comprising a charging station and a
robotic work tool, said robotic work tool comprising a position
determining device and a controller, wherein said controller is
configured to: determine a current position for the robotic work
tool based on the position determining device; determine a first
distance from the current position to said charging station; cause
said robotic work tool to travel a predetermined distance or for a
predetermined time; determine a new current position for the
robotic work tool based on the position determining device;
determine a second distance from the new current position to said
charging station; determine if the second distance is larger than
the first distance; and if so, cause the robotic work tool to turn
towards the charging station.
2. The robotic work tool system according to claim 1, wherein the
controller is further configured to cause the robotic work tool to
turn towards the charging station by determining a current heading
of the robotic work tool and to determine an angle between the
current heading and the position of the charging station and cause
the robotic work tool to turn the angle.
3. The robotic work tool system according to claim 1, wherein the
controller is further configured to determine if an obstacle is
blocking a route between the robotic work tool and the charging
station and if so cause said robotic work tool to travel a
predetermined distance or for a predetermined time.
4. The robotic work tool system according to claim 1, wherein the
controller is further configured to determine the distance to the
charging station based on coordinates of the charging station and
wherein the coordinates are stored as part of a map application in
a memory of said robotic work tool.
5. The robotic work tool system according to claim 1, wherein if
the second distance is not larger than the first distance, the
controller is configured to: cause said robotic work tool to travel
the predetermined distance or for the predetermined time; determine
a new current position for the robotic work tool based on the
position determining device; determine a new second distance from
the new current position to said charging station, wherein a new
first position is set to be the old second distance; determine if
the new second distance is larger than the first distance; and if
so, cause the robotic work tool to turn towards the charging
station.
6. The robotic work tool system according to claim 1, wherein the
robotic work tool is a robotic lawnmower.
7. The robotic work tool system according to claim 1, wherein the
position determining device is a global positioning device.
8. The robotic work tool system according to claim 1, wherein the
robotic work tool is caused to travel along a boundary wire
comprised in the robotic work tool system.
9. A method for use in a robotic work tool system robotic work tool
system comprising a charging station and a robotic work tool, said
robotic work tool comprising a position determining device, wherein
said method comprises: determining a current position for the
robotic work tool based on the position determining device;
determining a first distance from the current position to said
charging station; causing said robotic work tool to travel a
predetermined distance or for a predetermined time; determining a
new current position for the robotic work tool based on the
position determining device; determining a second distance from the
new current position to said charging station; determining if the
second distance is larger than the first distance; and if so,
causing the robotic work tool to turn towards the charging station.
Description
TECHNICAL FIELD
[0001] This application relates to a robotic work tool system for
improved navigation, and in particular to a robotic work tool
system for improved navigation to a charging station.
BACKGROUND
[0002] Many robotic work tool systems are enabled to allow the
robotic work tool to find a charging station by either following
the boundary following a so called F-field. However, if the F-field
can not be sensed or if the route in the F-field is blocked, the
robotic work tool may waste time and power trying to find the
charging station.
[0003] Using positioning devices such as GPS (Global Positioning
System) to navigate for example a robotic lawnmower may lead to
that the robotic work tool navigates incorrectly at times or places
where satellite reception is compromised, for example by threes or
structures, commonly found in for example gardens.
[0004] There is thus a need for a robotic work tool system with a
robotic work tool that is able to find its way to charging station
without wasting time or power, while relying on traditional
navigational methods.
SUMMARY
[0005] It is an object of the teachings of this application to
overcome the problems listed above by providing robotic work tool
system comprising a charging station and a robotic work tool, said
robotic work tool comprising a position determining device and a
controller, wherein said controller is configured to determine a
current position for the robotic work tool based on the position
determining device, determine a first distance from the current
position to said charging station, cause said robotic work tool to
travel a predetermined distance or for a predetermined time,
determine a new current position for the robotic work tool based on
the position determining device, determine a second distance from
the new current position to said charging station, determine if the
second distance is larger than the first distance; and if so, cause
the robotic work tool to turn towards the charging station.
[0006] In one embodiment the robotic work tool is a robotic
lawnmower. In one embodiment the robotic work tool 100 is a farming
equipment. In one embodiment the robotic work tool 100 is a golf
ball collecting tool. The robotic work tool 100 may also be a
vacuum cleaner, a floor cleaner, a street sweeper, a snow removal
tool, a mine clearance robot or any other robotic work tool that is
required to operate in a work area in a methodical and systematic
or position oriented manner.
[0007] It is also an object of the teachings of this application to
overcome the problems listed above by providing method for use in a
robotic work tool system comprising charging station and a robotic
work tool, said robotic work tool comprising a position determining
device, wherein said method comprises: determining a current
position for the robotic work tool based on the position
determining device; determining a first distance from the current
position to said charging station; causing said robotic work tool
to travel a predetermined distance or for a predetermined time;
determining a new current position for the robotic work tool based
on the position determining device; determining a second distance
from the new current position to said charging station; determining
if the second distance is larger than the first distance; and if
so, causing the robotic work tool to turn towards the charging
station.
[0008] The inventors of the present invention have realized, after
inventive and insightful reasoning, that a robotic work tool
configured to follow a boundary wire for as long as possible before
leaving to travel to the charging station and by determining when
the distance to the charging station is the shortest a virtual
F-field is provided which allows the robotic work tool to use tried
and reliable navigational methods while not wasting time or power
looking for the charging station.
[0009] Other features and advantages of the disclosed embodiments
will appear from the following detailed disclosure, from the
attached dependent claims as well as from the drawings.
[0010] Generally, all terms used in the claims are to be
interpreted according to their ordinary meaning in the technical
field, unless explicitly defined otherwise herein. All references
to "a/an/the [element, device, component, means, step, etc]" are to
be interpreted openly as referring to at least one instance of the
element, device, component, means, step, etc., unless explicitly
stated otherwise. The steps of any method disclosed herein do not
have to be performed in the exact order disclosed, unless
explicitly stated.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The invention will be described in further detail under
reference to the accompanying drawings in which:
[0012] FIG. 1 shows a schematic overview of a robotic work tool
according to one embodiment of the teachings of this
application;
[0013] FIG. 2 shows a schematic view of a robotic working tool
system according to one embodiment of the teachings of this
application;
[0014] FIG. 3 shows a schematic overview of a robotic work tool
system illustrating a problem with the contemporary use of F-fields
for finding the charging station;
[0015] FIG. 4 shows a schematic overview of a robotic work tool
system according to the teachings herein for overcoming the
problems of the prior art;
[0016] FIG. 5 shows an overview of an example robotic work tool
system where an obstacle is blocking the closest route from the
robotic work tool to the charging station;
[0017] FIG. 6 shows an overview of an example robotic work tool
system where the robotic work tool has moved away from the obstacle
and the obstacle is no longer blocking the route from the robotic
work tool to the charging station; and
[0018] FIG. 7 shows a general flowchart for a method for operating
a robotic work tool according to herein.
DETAILED DESCRIPTION
[0019] The disclosed embodiments will now be described more fully
hereinafter with reference to the accompanying drawings, in which
certain embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided by way of example so that this
disclosure will be thorough and complete, and will fully convey the
scope of the invention to those skilled in the art. Like numbers
refer to like elements throughout.
[0020] FIG. 1 shows a schematic overview of a robotic work tool 100
having a body 140 and a plurality of wheels 130. In the exemplary
embodiment of FIG. 1 the robotic work tool 100 has 4 wheels 130,
two front wheels 130' and the rear wheels 130''. At least some of
the wheels 130 are drivably connected to at least one electric
motor 150. It should be noted that even if the description herein
is focussed on electric motors, combustion engines may
alternatively be used possibly in combination with an electric
motor.
[0021] In the example of FIG. 1, the rear wheels 130'' are
connected to each an electric motor 150. This allows for driving
the rear wheels 130'' independently of one another which, for
example, enables steep turning.
[0022] The robotic work tool 100 also comprises a controller 110.
The controller 110 may be implemented using instructions that
enable hardware functionality, for example, by using executable
computer program instructions in a general-purpose or
special-purpose processor that may be stored on a computer readable
storage medium (disk, memory etc) 120 to be executed by such a
processor. The controller 110 is configured to read instructions
from the memory 120 and execute these instructions to control the
operation of the robotic work tool 100. The controller 110 may be
implemented using any suitable, publically available processor or
Programmable Logic Circuit (PLC). The memory 120 may be used for
storing various instructions and data, such as a map application M
and may be implemented using any commonly known technology for
computer-readable memories such as ROM, RAM, SRAM, DRAM, FLASH,
DDR, SDRAM or some other memory technology.
[0023] The robotic work tool 100 further has at least one sensor
170, in the example of FIG. 1 there are two sensors 170, arranged
to detect a magnetic field (not shown). The sensors are connected
to the controller 110 and the controller 110 is configured to
process any signals received from the sensors 170. The sensor
signals may be caused by the magnetic field caused by a control
signal being transmitted through a boundary wire (for more details
on charging stations, control signals and boundary wires, see the
description below with reference to FIG. 2). This enables the
controller 110 to determine whether the robotic work tool 100 is
inside or outside an area (referenced 205 in FIG. 2) enclosed by a
boundary wire (referenced 250 in FIG. 2).
[0024] The controller 110 is connected to the motors 150 for
controlling the propulsion of the robotic work tool 100 which
enables the robotic work tool 100 to service an enclosed area
without leaving the area.
[0025] The robotic work tool 100 also comprises a work tool 160,
which may be a grass cutting device, such as a rotating blade 160
driven by a cutter motor 165. The cutter motor 165 is connected to
the controller 110 which enables the controller 110 to control the
operation of the cutter motor 165. The controller is also
configured to determine the load exerted on the rotating blade, by
for example measure the power delivered to the cutter motor 165 or
by measuring the axle torque exerted by the rotating blade. The
robotic work tool 100 is, in one embodiment, a robotic
lawnmower.
[0026] The robotic work tool 100 may also have (at least) one
battery 180 for providing power to the motors 150 and the cutter
motor 165. Connected to the battery 180 are two charging connectors
for receiving a charging current from a charger (referenced 220 in
FIG. 2) of the charging station (referenced 210 in FIG. 2).
[0027] Alternatively, the batteries may be solar charged.
[0028] Alternatively, the robotic work tool and/or the cutter may
be driven by an engine.
[0029] The robotic work tool 100 is also arranged with a position
determining device 190, such as a GNSS (Global Navigation Satellite
System) device 190. In one embodiment the GNSS device is a GPS
(Global Positioning Service) device 190. The GNSS device 190 is
connected to the controller 110 for enabling the controller 110 to
determine a current position for the robotic work tool 100 using
the GNSS device and to control the movements of the robotic work
tool 100 based on the position. Other examples of position
determining devices 190 include optical (such as laser) position
determining devices, other radio frequency position determining
systems, and ultrawideband (UWB) beacons and receivers.
[0030] FIG. 2 shows a schematic view of a robotic working tool
system 200 comprising a charging station 210 and a boundary wire
250 arranged to enclose a working area 205, the working area 205
not necessarily being a part of the robot system 200.
[0031] The robotic work tool 100 of FIG. 2 is a robotic work tool
100 such as disclosed with reference to FIG. 1. A charging station
210 has a charger 220 coupled to, in this embodiment, two charging
connectors 230. The charging connectors 230 are arranged to
co-operate with corresponding charging connectors 185 of the
robotic work tool 100 for charging the battery 180 of the robotic
work tool 100.
[0032] The charging station 210 also has, or may be coupled to, a
signal generator 240 for providing a control signal 255 (for more
details see FIG. 3) to be transmitted through the boundary wire
250. As is known in the art, the current pulses 255 will generate a
magnetic field around the boundary wire 250 which the sensors 170
of the robotic work tool 100 will detect. As the robotic work tool
100 (or more accurately, the sensor 170) crosses the boundary wire
250 the direction of the magnetic field will change. The robotic
work tool 100 will thus be able to determine that the boundary wire
has been crossed.
[0033] Optionally, the charging station 210 also has a guide cable
260 for enabling the robot to find the entrance of the charging
station 210. In one embodiment the guide cable 260 is formed by a
loop of the boundary wire 250.
[0034] In one alternative or additional embodiment the guide wire
260 is used to generate a magnetic field for enabling the robotic
work tool 100 to find the charging station without following a
guide cable 260. Such a magnetic field is commonly referred to as
an F-field 270 and the robotic work tool is configured to navigate
to the charging station 210 by navigating towards an increasing
field strength for the F-field 270. The F-field 270 may have its
center at the charging station or at the guide wire 260. In the
latter case the F-field 270 can be used to enable the robotic work
tool 100 to find the guide cable 260 or the charging station 210
more quickly as it can jump the boundary wire as it senses the
magnetic field from the F-field 270. In one embodiment the magnetic
field from the F-field 270 is differentiated from the magnetic
field of the boundary wire 250 through a difference in the control
signal 255 being transmitted through the boundary wire 250 and the
control signal generating the F-field 270.
[0035] The robotic work tool 100 may be configured to find the
charging station 210 using the F-field 270 in different manners.
One alternative is that the robotic work tool 100 randomly
traverses the work area 205 until it finds the F-field 270. Another
alternative is that the robotic work tool 100 follows the boundary
wire 250 until it finds the F-field 270 and then shortcuts from the
boundary wire 250 to the charging station 210 following the F-field
270.
[0036] Combinations of these alternatives are of course also
possible, and also timed or distance-based combinations are
possible. For example, a robotic work tool 100 may be configured to
randomly search for the F-field 270 for 5 minutes, or spend time
trying to find the F-field 270, and if no F-field 270 has been
found, then the robotic work tool 100 follows the boundary wire 250
until the charging station 210 or the F-field 270 is found.
[0037] It should be noted that many other manners of generating the
F-field also exist and are known in the field of robotic work
tools.
[0038] FIG. 3 shows a schematic overview of a robotic work tool
system 200, such as the robotic work tool system 200 of FIG. 2,
illustrating a problem with the contemporary use of F-fields 270
for finding the charging station 210. In the situation depicted in
FIG. 3, the robotic work tool is too far away to sense the F-field
270 and is headed away from the charging station 210. The robotic
work tool 100 will have to follow the boundary wire 250 all around
to find the charging station 210. Alternatively, the robotic work
tool 100 will jump the boundary wire 250 and start searching
randomly for the ff270. In any case, the robotic work tool's
current heading is taking the robotic work tool 100 away from the
charging station 210 and runtime is lost trying to find a way back
to the charging station 210 unnecessarily using the manners of the
prior art to find the charging station 210.
[0039] However, by utilizing a position determining device, such as
a GPS device 190, in combination with a map application (referenced
M in FIG. 1) stored in the memory 120 of the robotic work tool 100
an improved manner of finding the way to the charging station 210
is provided. FIG. 4 shows a schematic overview of a robotic work
tool system 200 according to the teachings herein for overcoming
the problems of the prior art utilizing a GPS device 190 in
combination with a map application M finding the way to the
charging station 210.
[0040] The map application M may in its simplest form simply
consist of coordinates for the charging station 210 or the guide
cable 260. In the Example of FIG. 4 the map application M is simply
the coordinates (X;Y) for the guide cable 260. Other more advanced
maps such as being defined by Autoset 2.5 may also be used as will
be discussed further below.
[0041] The robotic work tool 100 may be configured to utilize a
virtual F-field 410 for finding the way to the charging station 210
(possibly via the guide cable 260). The virtual F-field 410 may be
defined as an area within which there exists an alternative route
to the charging station 210. The virtual F-field 410 may for
example be defined using coordinates in the map application M.
[0042] To enable a faster localization of the charging station 210,
the robotic work tool 100 is configured to determine a current
position of the robotic work tool 100 and to determine whether the
robotic work tool 100 is within the virtual F-field 410. If so, the
robotic work tool 100 is configured to determine a (alternative)
route to the charging station 210, wherein said route does not
fully follow the boundary wire 250.
[0043] In the example of FIG. 4, the robotic work tool 100 is
configured to determine that it is at a first distance to the
charging station 210 or the guide cable 260 based on the map
application M and the current position of the robotic work tool 100
(as the guide cable 260 leads to the charging station 210, there
will not be made any difference between the distance to the
charging station 210 and the distance to the guide cable 260 and
the distance of the guide cable to the charging station 210 will be
taken to be part of the distance between the robotic work tool 100
and the charging station 210). As the robotic work tool 100 moves
forward a new current position and a second distance to the
charging station 210 are determined by the robotic work tool 100
and the second distance is compared to the first distance. As long
as the second distance is shorter than the first distance the
robotic work tool moves forward and determines a new second
distance, wherein the new first distance is set to the old second
distance and the comparison is repeated. That the second distance
is larger than the first distance indicates that the robotic work
tool 100 is moving towards the charging station 210.
[0044] When it is determined by the robotic work tool 100 that the
second distance becomes larger or is the same as the first
distance--which indicates that the robotic work tool 100 is moving
a way from the charging station 210--a current heading of the
robotic work tool 100 and an angle A between the current heading of
the robotic work tool 100 and the position of the charging station
210 are determined and the robotic work tool 100 is caused to turn
that angle A and continue moving towards the robotic work tool 100.
This should enable the robotic work tool 100 to find at least the
F-field 270 or the guide cable 260 without any further advanced
navigational procedures and also without unnecessarily spending
time looking for the charging station 210.
[0045] By following the boundary cable 250 a reliable and tested
navigation method is used as long as necessary, which navigation
method is not dependent on clear satellite coverage or other
environmental factors.
[0046] Alternatively the robotic work tool releases from the
boundary wire 250 before the route to the charging station 210 is
blocked by the obstacle 510.
[0047] In some embodiments the map application M may be expanded to
include coordinates or boundaries for obstacles, such as a bush,
shrubbery, tree, pond or other obstacle, and/or shapes of the work
area.
[0048] FIG. 5 shows an overview of an example robotic work tool
system 200 where an obstacle 510 is blocking the closest route from
the robotic work tool 100 to the charging station 210. As the
robotic work tool 100 would determine that the second distance is
larger than the first distance the robotic work tool 100 would be
prevented from travelling straight to the charging station 210 as
the route is blocked by an obstacle, such as a bush 510. Circum
navigating the obstacle 510 may send the robotic work tool 100 in a
direction that is away from the charging station 210. To prevent
this and alleviate any problems caused by obstacles 510, the map
application M further comprises coordinates or other information on
obstacles 510 and as the robotic work tool determines that the
second distance is larger than the first distance, the robotic work
tool 100 is configured to determine if there is an obstacle 510
blocking the route to the charging station 210. If so, the robotic
work tool 100 is configured to continue travel along the boundary
wire 250 until the route from the robotic work tool 100 to the
charging station 210 is no longer blocked by an obstacle 510. An
obstacle may be determined to block a route between the robotic
work tool 100 and the charging station 210 if coordinates for the
obstacle 510, which coordinates may define an area of extension for
the obstacle 510, is between the coordinates for the charging
station 210 and the current position of the robotic work tool
100.
[0049] The robotic work tool 100 may also or alternatively be
configured to proactively determine if an obstacle 510 will block a
route between the robotic work tool 100 and the charging station
210 as the robotic work tool 100 continues travelling in its
current heading and if so, determine whether to turn towards the
charging station 210 even if the second distance is smaller than
the first distance. Such determination may be made based on an
extension of the obstacle 510. If it is determined that the
obstacle 510 will block the route, the robotic work tool 100 is
configured to determine a turn point where the route will not be
blocked, but is also close to the point where the second distance
equals the first distance.
[0050] FIG. 6 shows an overview of an example robotic work tool
system 200 where the robotic work tool 100 has moved away from the
obstacle 510 and the obstacle is no longer blocking the route from
the robotic work tool 100 to the charging station 210. An angle A
may then be determined and the robotic work tool 100 will turn that
angle A and travel towards the charging station 210.
[0051] FIG. 7 shows a general flowchart for a method for operating
a robotic work tool 100 according to herein. The method may be
stored as instructions on a computer readable storage medium and as
the instructions are loaded into and executed by a controller, the
method is executed.
[0052] The robotic work tool 100 determines 700 its current
position and determines 710 that the robotic work tool 100 is
within a virtual F-field 410. The robotic work tool 100 then
determines 720 a first distance to the charging station 210.
Thereafter the robotic work tool 100 travels 730 along the boundary
wire 250 for a predetermined time (such as 0.5, 1, 2, 5 or 10
seconds or continuously) or alternatively for a predetermined
distance (such as 0.1, 0.2, 0.5, 1, 2 or 5 meters) and then
determines 740 a new current position and determines 750 a second
distance to the charging station 210. The robotic work tool 100
compares 760 the first distance to the second distance and if the
second distance is smaller than the first distance, the robotic
work tool 100 continues to travel along the boundary wire
determining a new second distance, wherein a new first distance is
the old second distance and compares again. If the second distance
is larger than the first distance, the robotic work tool determines
770 an angle A from its current heading to the charging station 210
and turns that angle A, travelling towards the charging station
210.
[0053] What happens when the first distance equals the second
distance may depend on a number of factors, such as the time
travelled along eh boundary wire 250. In one embodiment the robotic
work tool 100 is configured to determine the angle A and turn and
travel towards the charging station 210. Alternatively, as is
indicated b the dashed box in FIG. 7, and as ahs been disclosed in
the above, the robotic work tool 100 may also be configured to
determine if an obstacle 510 is blocking the route 765 from the
robotic work tool 100 to the charging station 210, and if so,
continue to travel a long the boundary wire 250 until the route is
no longer blocked.
[0054] One benefit of the teachings herein is that tried
navigational methods are used to the fullest without wasting time
or energy trying to find the charging station 210. A navigation
system solely or primarily relying on for example GPS devices 190,
will in some situations suffer from bad satellite reception which
may cause the robotic work tool 100 to navigate incorrectly.
[0055] References to `computer-readable storage medium`, `computer
program product`, `tangibly embodied computer program` etc. or a
`controller`, `computer`, `processor` etc. should be understood to
encompass not only computers having different architectures such as
single/multi-processor architectures and sequential/parallel
architectures but also specialized circuits such as
field-programmable gate arrays (FPGA), application specific
circuits (ASIC), signal processing devices and other devices.
References to computer program, instructions, code etc. should be
understood to encompass software for a programmable processor or
firmware such as, for example, the programmable content of a
hardware device whether instructions for a processor, or
configuration settings for a fixed-function device, gate array or
programmable logic device etc.
[0056] The invention has mainly been described above with reference
to a few embodiments. However, as is readily appreciated by a
person skilled in the art, other embodiments than the ones
disclosed above are equally possible within the scope of the
invention, as defined by the appended patent claims.
* * * * *